The present invention relates generally to the production of methyl mercaptan. More particularly, the invention relates processes producing methyl mercaptan by the reaction of methyl bromide with sodium hydrosulfide, and which can be implemented to convert both sodium hydrosulfide and methyl bromide byproducts to the more desirable methyl mercaptan.
As further background, two very significant problems that face bromine (Br.sub.2) producers and utilizers involve hydrogen sulfide (H.sub.2 S) and methyl bromide (CH.sub.3 Br). The H.sub.2 S problem is the result of bromine recovery. Geothermal brine formations, for example those occurring in the Southern United States, are a rich source of bromine. Several Br.sub.2 producing companies "mine" this brine with wells. To produce Br.sub.2, bromide ions in the brine are oxidized with Cl.sub.2 and Br.sub.2 is recovered. Unfortunately, brine from geothermal formations can also contain significant quantities of H.sub.2 S, which must be stripped from the brine. H.sub.2 S cannot be burned or released into the atmosphere without posing safety or environmental concerns and has thus been regulated in a number of countries Therefore, H.sub.2 S has traditionally been absorbed in NaOH to form sodium hydrosulfide (NaSH).
Until recently, NaSH was utilized in large quantities by the paper industry. However, a combination of industry-specific changes and tightening of sulfur emission rules by regulatory agencies such as the Environmental Protection Agency (EPA) in the U.S. have produced a significant glut in the NaSH market. One alternative is to produce sulfur; however, difficulties are also encountered in attempting to find a market outlet for sulfur.
A second obstacle, encountered in the flame retardant industry, relates to the production of substantial quantities of methyl bromide (CH.sub.3 Br) in the manufacture of certain brominated flame retardants such as tetrabromobisphenol A. Methyl bromide is another material identified as posing health and safety concerns, and is the subject of regulation by agencies such as the EPA in the U.S. The obvious impact is the potential curtailment of critical flame retardant production.
Faced with these challenges there are critical needs in the bromine and flame retardant industries for means of ameliorating the limitations posed by NaSH and methyl bromide byproducts. The present invention addresses these needs.